net/9p/trans_rdma.c

   1 /*
   2  * linux/fs/9p/trans_rdma.c
   3  *
   4  * RDMA transport layer based on the trans_fd.c implementation.
   5  *
   6  *  Copyright (C) 2008 by Tom Tucker <tom@opengridcomputing.com>
   7  *  Copyright (C) 2006 by Russ Cox <rsc@swtch.com>
   8  *  Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
   9  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
  10  *  Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com>
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License version 2
  14  *  as published by the Free Software Foundation.
  15  *
  16  *  This program is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *  GNU General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License
  22  *  along with this program; if not, write to:
  23  *  Free Software Foundation
  24  *  51 Franklin Street, Fifth Floor
  25  *  Boston, MA  02111-1301  USA
  26  *
  27  */
  28
  29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  30
  31 #include <linux/in.h>
  32 #include <linux/module.h>
  33 #include <linux/net.h>
  34 #include <linux/ipv6.h>
  35 #include <linux/kthread.h>
  36 #include <linux/errno.h>
  37 #include <linux/kernel.h>
  38 #include <linux/un.h>
  39 #include <linux/uaccess.h>
  40 #include <linux/inet.h>
  41 #include <linux/idr.h>
  42 #include <linux/file.h>
  43 #include <linux/parser.h>
  44 #include <linux/semaphore.h>
  45 #include <linux/slab.h>
  46 #include <net/9p/9p.h>
  47 #include <net/9p/client.h>
  48 #include <net/9p/transport.h>
  49 #include <rdma/ib_verbs.h>
  50 #include <rdma/rdma_cm.h>
  51
  52 #define P9_PORT                 5640
  53 #define P9_RDMA_SQ_DEPTH        32
  54 #define P9_RDMA_RQ_DEPTH        32
  55 #define P9_RDMA_SEND_SGE        4
  56 #define P9_RDMA_RECV_SGE        4
  57 #define P9_RDMA_IRD             0
  58 #define P9_RDMA_ORD             0
  59 #define P9_RDMA_TIMEOUT         30000           /* 30 seconds */
  60 #define P9_RDMA_MAXSIZE         (1024*1024)     /* 1MB */
  61
  62 /**
  63  * struct p9_trans_rdma - RDMA transport instance
  64  *
  65  * @state: tracks the transport state machine for connection setup and tear down
  66  * @cm_id: The RDMA CM ID
  67  * @pd: Protection Domain pointer
  68  * @qp: Queue Pair pointer
  69  * @cq: Completion Queue pointer
  70  * @dm_mr: DMA Memory Region pointer
  71  * @lkey: The local access only memory region key
  72  * @timeout: Number of uSecs to wait for connection management events
  73  * @sq_depth: The depth of the Send Queue
  74  * @sq_sem: Semaphore for the SQ
  75  * @rq_depth: The depth of the Receive Queue.
  76  * @rq_sem: Semaphore for the RQ
  77  * @excess_rc : Amount of posted Receive Contexts without a pending request.
  78  *              See rdma_request()
  79  * @addr: The remote peer's address
  80  * @req_lock: Protects the active request list
  81  * @cm_done: Completion event for connection management tracking
  82  */
  83 struct p9_trans_rdma {
  84         enum {
  85                 P9_RDMA_INIT,
  86                 P9_RDMA_ADDR_RESOLVED,
  87                 P9_RDMA_ROUTE_RESOLVED,
  88                 P9_RDMA_CONNECTED,
  89                 P9_RDMA_FLUSHING,
  90                 P9_RDMA_CLOSING,
  91                 P9_RDMA_CLOSED,
  92         } state;
  93         struct rdma_cm_id *cm_id;
  94         struct ib_pd *pd;
  95         struct ib_qp *qp;
  96         struct ib_cq *cq;
  97         struct ib_mr *dma_mr;
  98         u32 lkey;
  99         long timeout;
 100         int sq_depth;
 101         struct semaphore sq_sem;
 102         int rq_depth;
 103         struct semaphore rq_sem;
 104         atomic_t excess_rc;
 105         struct sockaddr_in addr;
 106         spinlock_t req_lock;
 107
 108         struct completion cm_done;
 109 };
 110
 111 /**
 112  * p9_rdma_context - Keeps track of in-process WR
 113  *
 114  * @wc_op: The original WR op for when the CQE completes in error.
 115  * @busa: Bus address to unmap when the WR completes
 116  * @req: Keeps track of requests (send)
 117  * @rc: Keepts track of replies (receive)
 118  */
 119 struct p9_rdma_req;
 120 struct p9_rdma_context {
 121         enum ib_wc_opcode wc_op;
 122         dma_addr_t busa;
 123         union {
 124                 struct p9_req_t *req;
 125                 struct p9_fcall *rc;
 126         };
 127 };
 128
 129 /**
 130  * p9_rdma_opts - Collection of mount options
 131  * @port: port of connection
 132  * @sq_depth: The requested depth of the SQ. This really doesn't need
 133  * to be any deeper than the number of threads used in the client
 134  * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth
 135  * @timeout: Time to wait in msecs for CM events
 136  */
 137 struct p9_rdma_opts {
 138         short port;
 139         int sq_depth;
 140         int rq_depth;
 141         long timeout;
 142         int privport;
 143 };
 144
 145 /*
 146  * Option Parsing (code inspired by NFS code)
 147  */
 148 enum {
 149         /* Options that take integer arguments */
 150         Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout,
 151         /* Options that take no argument */
 152         Opt_privport,
 153         Opt_err,
 154 };
 155
 156 static match_table_t tokens = {
 157         {Opt_port, "port=%u"},
 158         {Opt_sq_depth, "sq=%u"},
 159         {Opt_rq_depth, "rq=%u"},
 160         {Opt_timeout, "timeout=%u"},
 161         {Opt_privport, "privport"},
 162         {Opt_err, NULL},
 163 };
 164
 165 /**
 166  * parse_opts - parse mount options into rdma options structure
 167  * @params: options string passed from mount
 168  * @opts: rdma transport-specific structure to parse options into
 169  *
 170  * Returns 0 upon success, -ERRNO upon failure
 171  */
 172 static int parse_opts(char *params, struct p9_rdma_opts *opts)
 173 {
 174         char *p;
 175         substring_t args[MAX_OPT_ARGS];
 176         int option;
 177         char *options, *tmp_options;
 178
 179         opts->port = P9_PORT;
 180         opts->sq_depth = P9_RDMA_SQ_DEPTH;
 181         opts->rq_depth = P9_RDMA_RQ_DEPTH;
 182         opts->timeout = P9_RDMA_TIMEOUT;
 183         opts->privport = 0;
 184
 185         if (!params)
 186                 return 0;
 187
 188         tmp_options = kstrdup(params, GFP_KERNEL);
 189         if (!tmp_options) {
 190                 p9_debug(P9_DEBUG_ERROR,
 191                          "failed to allocate copy of option string\n");
 192                 return -ENOMEM;
 193         }
 194         options = tmp_options;
 195
 196         while ((p = strsep(&options, ",")) != NULL) {
 197                 int token;
 198                 int r;
 199                 if (!*p)
 200                         continue;
 201                 token = match_token(p, tokens, args);
 202                 if ((token != Opt_err) && (token != Opt_privport)) {
 203                         r = match_int(&args[0], &option);
 204                         if (r < 0) {
 205                                 p9_debug(P9_DEBUG_ERROR,
 206                                          "integer field, but no integer?\n");
 207                                 continue;
 208                         }
 209                 }
 210                 switch (token) {
 211                 case Opt_port:
 212                         opts->port = option;
 213                         break;
 214                 case Opt_sq_depth:
 215                         opts->sq_depth = option;
 216                         break;
 217                 case Opt_rq_depth:
 218                         opts->rq_depth = option;
 219                         break;
 220                 case Opt_timeout:
 221                         opts->timeout = option;
 222                         break;
 223                 case Opt_privport:
 224                         opts->privport = 1;
 225                         break;
 226                 default:
 227                         continue;
 228                 }
 229         }
 230         /* RQ must be at least as large as the SQ */
 231         opts->rq_depth = max(opts->rq_depth, opts->sq_depth);
 232         kfree(tmp_options);
 233         return 0;
 234 }
 235
 236 static int
 237 p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 238 {
 239         struct p9_client *c = id->context;
 240         struct p9_trans_rdma *rdma = c->trans;
 241         switch (event->event) {
 242         case RDMA_CM_EVENT_ADDR_RESOLVED:
 243                 BUG_ON(rdma->state != P9_RDMA_INIT);
 244                 rdma->state = P9_RDMA_ADDR_RESOLVED;
 245                 break;
 246
 247         case RDMA_CM_EVENT_ROUTE_RESOLVED:
 248                 BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED);
 249                 rdma->state = P9_RDMA_ROUTE_RESOLVED;
 250                 break;
 251
 252         case RDMA_CM_EVENT_ESTABLISHED:
 253                 BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED);
 254                 rdma->state = P9_RDMA_CONNECTED;
 255                 break;
 256
 257         case RDMA_CM_EVENT_DISCONNECTED:
 258                 if (rdma)
 259                         rdma->state = P9_RDMA_CLOSED;
 260                 if (c)
 261                         c->status = Disconnected;
 262                 break;
 263
 264         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
 265                 break;
 266
 267         case RDMA_CM_EVENT_ADDR_CHANGE:
 268         case RDMA_CM_EVENT_ROUTE_ERROR:
 269         case RDMA_CM_EVENT_DEVICE_REMOVAL:
 270         case RDMA_CM_EVENT_MULTICAST_JOIN:
 271         case RDMA_CM_EVENT_MULTICAST_ERROR:
 272         case RDMA_CM_EVENT_REJECTED:
 273         case RDMA_CM_EVENT_CONNECT_REQUEST:
 274         case RDMA_CM_EVENT_CONNECT_RESPONSE:
 275         case RDMA_CM_EVENT_CONNECT_ERROR:
 276         case RDMA_CM_EVENT_ADDR_ERROR:
 277         case RDMA_CM_EVENT_UNREACHABLE:
 278                 c->status = Disconnected;
 279                 rdma_disconnect(rdma->cm_id);
 280                 break;
 281         default:
 282                 BUG();
 283         }
 284         complete(&rdma->cm_done);
 285         return 0;
 286 }
 287
 288 static void
 289 handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma,
 290             struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
 291 {
 292         struct p9_req_t *req;
 293         int err = 0;
 294         int16_t tag;
 295
 296         req = NULL;
 297         ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize,
 298                                                          DMA_FROM_DEVICE);
 299
 300         if (status != IB_WC_SUCCESS)
 301                 goto err_out;
 302
 303         err = p9_parse_header(c->rc, NULL, NULL, &tag, 1);
 304         if (err)
 305                 goto err_out;
 306
 307         req = p9_tag_lookup(client, tag);
 308         if (!req)
 309                 goto err_out;
 310
 311         /* Check that we have not yet received a reply for this request.
 312          */
 313         if (unlikely(req->rc)) {
 314                 pr_err("Duplicate reply for request %d", tag);
 315                 goto err_out;
 316         }
 317
 318         req->rc = c->rc;
 319         p9_client_cb(client, req, REQ_STATUS_RCVD);
 320
 321         return;
 322
 323  err_out:
 324         p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n", req, err, status);
 325         rdma->state = P9_RDMA_FLUSHING;
 326         client->status = Disconnected;
 327 }
 328
 329 static void
 330 handle_send(struct p9_client *client, struct p9_trans_rdma *rdma,
 331             struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len)
 332 {
 333         ib_dma_unmap_single(rdma->cm_id->device,
 334                             c->busa, c->req->tc->size,
 335                             DMA_TO_DEVICE);
 336 }
 337
 338 static void qp_event_handler(struct ib_event *event, void *context)
 339 {
 340         p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n",
 341                  event->event, context);
 342 }
 343
 344 static void cq_comp_handler(struct ib_cq *cq, void *cq_context)
 345 {
 346         struct p9_client *client = cq_context;
 347         struct p9_trans_rdma *rdma = client->trans;
 348         int ret;
 349         struct ib_wc wc;
 350
 351         ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
 352         while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) {
 353                 struct p9_rdma_context *c = (void *) (unsigned long) wc.wr_id;
 354
 355                 switch (c->wc_op) {
 356                 case IB_WC_RECV:
 357                         handle_recv(client, rdma, c, wc.status, wc.byte_len);
 358                         up(&rdma->rq_sem);
 359                         break;
 360
 361                 case IB_WC_SEND:
 362                         handle_send(client, rdma, c, wc.status, wc.byte_len);
 363                         up(&rdma->sq_sem);
 364                         break;
 365
 366                 default:
 367                         pr_err("unexpected completion type, c->wc_op=%d, wc.opcode=%d, status=%d\n",
 368                                c->wc_op, wc.opcode, wc.status);
 369                         break;
 370                 }
 371                 kfree(c);
 372         }
 373 }
 374
 375 static void cq_event_handler(struct ib_event *e, void *v)
 376 {
 377         p9_debug(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v);
 378 }
 379
 380 static void rdma_destroy_trans(struct p9_trans_rdma *rdma)
 381 {
 382         if (!rdma)
 383                 return;
 384
 385         if (rdma->dma_mr && !IS_ERR(rdma->dma_mr))
 386                 ib_dereg_mr(rdma->dma_mr);
 387
 388         if (rdma->qp && !IS_ERR(rdma->qp))
 389                 ib_destroy_qp(rdma->qp);
 390
 391         if (rdma->pd && !IS_ERR(rdma->pd))
 392                 ib_dealloc_pd(rdma->pd);
 393
 394         if (rdma->cq && !IS_ERR(rdma->cq))
 395                 ib_destroy_cq(rdma->cq);
 396
 397         if (rdma->cm_id && !IS_ERR(rdma->cm_id))
 398                 rdma_destroy_id(rdma->cm_id);
 399
 400         kfree(rdma);
 401 }
 402
 403 static int
 404 post_recv(struct p9_client *client, struct p9_rdma_context *c)
 405 {
 406         struct p9_trans_rdma *rdma = client->trans;
 407         struct ib_recv_wr wr, *bad_wr;
 408         struct ib_sge sge;
 409
 410         c->busa = ib_dma_map_single(rdma->cm_id->device,
 411                                     c->rc->sdata, client->msize,
 412                                     DMA_FROM_DEVICE);
 413         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa))
 414                 goto error;
 415
 416         sge.addr = c->busa;
 417         sge.length = client->msize;
 418         sge.lkey = rdma->lkey;
 419
 420         wr.next = NULL;
 421         c->wc_op = IB_WC_RECV;
 422         wr.wr_id = (unsigned long) c;
 423         wr.sg_list = &sge;
 424         wr.num_sge = 1;
 425         return ib_post_recv(rdma->qp, &wr, &bad_wr);
 426
 427  error:
 428         p9_debug(P9_DEBUG_ERROR, "EIO\n");
 429         return -EIO;
 430 }
 431
 432 static int rdma_request(struct p9_client *client, struct p9_req_t *req)
 433 {
 434         struct p9_trans_rdma *rdma = client->trans;
 435         struct ib_send_wr wr, *bad_wr;
 436         struct ib_sge sge;
 437         int err = 0;
 438         unsigned long flags;
 439         struct p9_rdma_context *c = NULL;
 440         struct p9_rdma_context *rpl_context = NULL;
 441
 442         /* When an error occurs between posting the recv and the send,
 443          * there will be a receive context posted without a pending request.
 444          * Since there is no way to "un-post" it, we remember it and skip
 445          * post_recv() for the next request.
 446          * So here,
 447          * see if we are this `next request' and need to absorb an excess rc.
 448          * If yes, then drop and free our own, and do not recv_post().
 449          **/
 450         if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
 451                 if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
 452                         /* Got one ! */
 453                         kfree(req->rc);
 454                         req->rc = NULL;
 455                         goto dont_need_post_recv;
 456                 } else {
 457                         /* We raced and lost. */
 458                         atomic_inc(&rdma->excess_rc);
 459                 }
 460         }
 461
 462         /* Allocate an fcall for the reply */
 463         rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
 464         if (!rpl_context) {
 465                 err = -ENOMEM;
 466                 goto recv_error;
 467         }
 468         rpl_context->rc = req->rc;
 469
 470         /*
 471          * Post a receive buffer for this request. We need to ensure
 472          * there is a reply buffer available for every outstanding
 473          * request. A flushed request can result in no reply for an
 474          * outstanding request, so we must keep a count to avoid
 475          * overflowing the RQ.
 476          */
 477         if (down_interruptible(&rdma->rq_sem)) {
 478                 err = -EINTR;
 479                 goto recv_error;
 480         }
 481
 482         err = post_recv(client, rpl_context);
 483         if (err) {
 484                 p9_debug(P9_DEBUG_FCALL, "POST RECV failed\n");
 485                 goto recv_error;
 486         }
 487         /* remove posted receive buffer from request structure */
 488         req->rc = NULL;
 489
 490 dont_need_post_recv:
 491         /* Post the request */
 492         c = kmalloc(sizeof *c, GFP_NOFS);
 493         if (!c) {
 494                 err = -ENOMEM;
 495                 goto send_error;
 496         }
 497         c->req = req;
 498
 499         c->busa = ib_dma_map_single(rdma->cm_id->device,
 500                                     c->req->tc->sdata, c->req->tc->size,
 501                                     DMA_TO_DEVICE);
 502         if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) {
 503                 err = -EIO;
 504                 goto send_error;
 505         }
 506
 507         sge.addr = c->busa;
 508         sge.length = c->req->tc->size;
 509         sge.lkey = rdma->lkey;
 510
 511         wr.next = NULL;
 512         c->wc_op = IB_WC_SEND;
 513         wr.wr_id = (unsigned long) c;
 514         wr.opcode = IB_WR_SEND;
 515         wr.send_flags = IB_SEND_SIGNALED;
 516         wr.sg_list = &sge;
 517         wr.num_sge = 1;
 518
 519         if (down_interruptible(&rdma->sq_sem)) {
 520                 err = -EINTR;
 521                 goto send_error;
 522         }
 523
 524         /* Mark request as `sent' *before* we actually send it,
 525          * because doing if after could erase the REQ_STATUS_RCVD
 526          * status in case of a very fast reply.
 527          */
 528         req->status = REQ_STATUS_SENT;
 529         err = ib_post_send(rdma->qp, &wr, &bad_wr);
 530         if (err)
 531                 goto send_error;
 532
 533         /* Success */
 534         return 0;
 535
 536  /* Handle errors that happened during or while preparing the send: */
 537  send_error:
 538         req->status = REQ_STATUS_ERROR;
 539         kfree(c);
 540         p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
 541
 542         /* Ach.
 543          *  We did recv_post(), but not send. We have one recv_post in excess.
 544          */
 545         atomic_inc(&rdma->excess_rc);
 546         return err;
 547
 548  /* Handle errors that happened during or while preparing post_recv(): */
 549  recv_error:
 550         kfree(rpl_context);
 551         spin_lock_irqsave(&rdma->req_lock, flags);
 552         if (rdma->state < P9_RDMA_CLOSING) {
 553                 rdma->state = P9_RDMA_CLOSING;
 554                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 555                 rdma_disconnect(rdma->cm_id);
 556         } else
 557                 spin_unlock_irqrestore(&rdma->req_lock, flags);
 558         return err;
 559 }
 560
 561 static void rdma_close(struct p9_client *client)
 562 {
 563         struct p9_trans_rdma *rdma;
 564
 565         if (!client)
 566                 return;
 567
 568         rdma = client->trans;
 569         if (!rdma)
 570                 return;
 571
 572         client->status = Disconnected;
 573         rdma_disconnect(rdma->cm_id);
 574         rdma_destroy_trans(rdma);
 575 }
 576
 577 /**
 578  * alloc_rdma - Allocate and initialize the rdma transport structure
 579  * @opts: Mount options structure
 580  */
 581 static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
 582 {
 583         struct p9_trans_rdma *rdma;
 584
 585         rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL);
 586         if (!rdma)
 587                 return NULL;
 588
 589         rdma->sq_depth = opts->sq_depth;
 590         rdma->rq_depth = opts->rq_depth;
 591         rdma->timeout = opts->timeout;
 592         spin_lock_init(&rdma->req_lock);
 593         init_completion(&rdma->cm_done);
 594         sema_init(&rdma->sq_sem, rdma->sq_depth);
 595         sema_init(&rdma->rq_sem, rdma->rq_depth);
 596         atomic_set(&rdma->excess_rc, 0);
 597
 598         return rdma;
 599 }
 600
 601 static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
 602 {
 603         /* Nothing to do here.
 604          * We will take care of it (if we have to) in rdma_cancelled()
 605          */
 606         return 1;
 607 }
 608
 609 /* A request has been fully flushed without a reply.
 610  * That means we have posted one buffer in excess.
 611  */
 612 static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
 613 {
 614         struct p9_trans_rdma *rdma = client->trans;
 615         atomic_inc(&rdma->excess_rc);
 616         return 0;
 617 }
 618
 619 static int p9_rdma_bind_privport(struct p9_trans_rdma *rdma)
 620 {
 621         struct sockaddr_in cl = {
 622                 .sin_family = AF_INET,
 623                 .sin_addr.s_addr = htonl(INADDR_ANY),
 624         };
 625         int port, err = -EINVAL;
 626
 627         for (port = P9_DEF_MAX_RESVPORT; port >= P9_DEF_MIN_RESVPORT; port--) {
 628                 cl.sin_port = htons((ushort)port);
 629                 err = rdma_bind_addr(rdma->cm_id, (struct sockaddr *)&cl);
 630                 if (err != -EADDRINUSE)
 631                         break;
 632         }
 633         return err;
 634 }
 635
 636 /**
 637  * trans_create_rdma - Transport method for creating atransport instance
 638  * @client: client instance
 639  * @addr: IP address string
 640  * @args: Mount options string
 641  */
 642 static int
 643 rdma_create_trans(struct p9_client *client, const char *addr, char *args)
 644 {
 645         int err;
 646         struct p9_rdma_opts opts;
 647         struct p9_trans_rdma *rdma;
 648         struct rdma_conn_param conn_param;
 649         struct ib_qp_init_attr qp_attr;
 650         struct ib_device_attr devattr;
 651         struct ib_cq_init_attr cq_attr = {};
 652
 653         /* Parse the transport specific mount options */
 654         err = parse_opts(args, &opts);
 655         if (err < 0)
 656                 return err;
 657
 658         /* Create and initialize the RDMA transport structure */
 659         rdma = alloc_rdma(&opts);
 660         if (!rdma)
 661                 return -ENOMEM;
 662
 663         /* Create the RDMA CM ID */
 664         rdma->cm_id = rdma_create_id(p9_cm_event_handler, client, RDMA_PS_TCP,
 665                                      IB_QPT_RC);
 666         if (IS_ERR(rdma->cm_id))
 667                 goto error;
 668
 669         /* Associate the client with the transport */
 670         client->trans = rdma;
 671
 672         /* Bind to a privileged port if we need to */
 673         if (opts.privport) {
 674                 err = p9_rdma_bind_privport(rdma);
 675                 if (err < 0) {
 676                         pr_err("%s (%d): problem binding to privport: %d\n",
 677                                __func__, task_pid_nr(current), -err);
 678                         goto error;
 679                 }
 680         }
 681
 682         /* Resolve the server's address */
 683         rdma->addr.sin_family = AF_INET;
 684         rdma->addr.sin_addr.s_addr = in_aton(addr);
 685         rdma->addr.sin_port = htons(opts.port);
 686         err = rdma_resolve_addr(rdma->cm_id, NULL,
 687                                 (struct sockaddr *)&rdma->addr,
 688                                 rdma->timeout);
 689         if (err)
 690                 goto error;
 691         err = wait_for_completion_interruptible(&rdma->cm_done);
 692         if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED))
 693                 goto error;
 694
 695         /* Resolve the route to the server */
 696         err = rdma_resolve_route(rdma->cm_id, rdma->timeout);
 697         if (err)
 698                 goto error;
 699         err = wait_for_completion_interruptible(&rdma->cm_done);
 700         if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED))
 701                 goto error;
 702
 703         /* Query the device attributes */
 704         err = ib_query_device(rdma->cm_id->device, &devattr);
 705         if (err)
 706                 goto error;
 707
 708         /* Create the Completion Queue */
 709         cq_attr.cqe = opts.sq_depth + opts.rq_depth + 1;
 710         rdma->cq = ib_create_cq(rdma->cm_id->device, cq_comp_handler,
 711                                 cq_event_handler, client,
 712                                 &cq_attr);
 713         if (IS_ERR(rdma->cq))
 714                 goto error;
 715         ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP);
 716
 717         /* Create the Protection Domain */
 718         rdma->pd = ib_alloc_pd(rdma->cm_id->device);
 719         if (IS_ERR(rdma->pd))
 720                 goto error;
 721
 722         /* Cache the DMA lkey in the transport */
 723         rdma->dma_mr = NULL;
 724         if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)
 725                 rdma->lkey = rdma->cm_id->device->local_dma_lkey;
 726         else {
 727                 rdma->dma_mr = ib_get_dma_mr(rdma->pd, IB_ACCESS_LOCAL_WRITE);
 728                 if (IS_ERR(rdma->dma_mr))
 729                         goto error;
 730                 rdma->lkey = rdma->dma_mr->lkey;
 731         }
 732
 733         /* Create the Queue Pair */
 734         memset(&qp_attr, 0, sizeof qp_attr);
 735         qp_attr.event_handler = qp_event_handler;
 736         qp_attr.qp_context = client;
 737         qp_attr.cap.max_send_wr = opts.sq_depth;
 738         qp_attr.cap.max_recv_wr = opts.rq_depth;
 739         qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE;
 740         qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE;
 741         qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
 742         qp_attr.qp_type = IB_QPT_RC;
 743         qp_attr.send_cq = rdma->cq;
 744         qp_attr.recv_cq = rdma->cq;
 745         err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr);
 746         if (err)
 747                 goto error;
 748         rdma->qp = rdma->cm_id->qp;
 749
 750         /* Request a connection */
 751         memset(&conn_param, 0, sizeof(conn_param));
 752         conn_param.private_data = NULL;
 753         conn_param.private_data_len = 0;
 754         conn_param.responder_resources = P9_RDMA_IRD;
 755         conn_param.initiator_depth = P9_RDMA_ORD;
 756         err = rdma_connect(rdma->cm_id, &conn_param);
 757         if (err)
 758                 goto error;
 759         err = wait_for_completion_interruptible(&rdma->cm_done);
 760         if (err || (rdma->state != P9_RDMA_CONNECTED))
 761                 goto error;
 762
 763         client->status = Connected;
 764
 765         return 0;
 766
 767 error:
 768         rdma_destroy_trans(rdma);
 769         return -ENOTCONN;
 770 }
 771
 772 static struct p9_trans_module p9_rdma_trans = {
 773         .name = "rdma",
 774         .maxsize = P9_RDMA_MAXSIZE,
 775         .def = 0,
 776         .owner = THIS_MODULE,
 777         .create = rdma_create_trans,
 778         .close = rdma_close,
 779         .request = rdma_request,
 780         .cancel = rdma_cancel,
 781         .cancelled = rdma_cancelled,
 782 };
 783
 784 /**
 785  * p9_trans_rdma_init - Register the 9P RDMA transport driver
 786  */
 787 static int __init p9_trans_rdma_init(void)
 788 {
 789         v9fs_register_trans(&p9_rdma_trans);
 790         return 0;
 791 }
 792
 793 static void __exit p9_trans_rdma_exit(void)
 794 {
 795         v9fs_unregister_trans(&p9_rdma_trans);
 796 }
 797
 798 module_init(p9_trans_rdma_init);
 799 module_exit(p9_trans_rdma_exit);
 800
 801 MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
 802 MODULE_DESCRIPTION("RDMA Transport for 9P");
 803 MODULE_LICENSE("Dual BSD/GPL");